The invention relates to an apparatus and method for refinishing the fingerboard frets of a fretted stringed instrument.
The invention relates more particularly to a method and apparatus which may be used for leveling the frets of a fretted stringed instrument and thereafter properly peaking or polishing the frets, with the removal of any burrs formed in the leveling procedure.
Refinishing, reconditioning, reshaping, dressing or truing the frets of a fretted stringed instrument, have heretofore normally required:
1. REMOVAL OF THE STRINGS FROM ABOVE THE FINGERBOARD, EITHER BY REMOVAL FROM THE INSTRUMENT OR BY STRETCHING THE STRINGS APART;
2. LEVELING OR DRESSING THE FRETS TO EXTEND ABOUT THE SAME HEIGHT ABOVE THE FINGERBOARD, USUALLY BY FILING OR SANDING, WHEREBY ANY GROOVES WHICH MAY HAVE BEEN FORMED BY WEARING AGAINST THE STRINGS, ARE REMOVED; AND
3. PEAKING OR POLISHING AND REMOVAL BY FILING OR SANDING OF ANY BURRS THAT MAY HAVE FORMED ON THE FRET, USUALLY BY CUTTING THE LONGITUDINAL EDGES AT AN ANGLE AT THE TOP.
This or similar refinishing techniques have been described in a number of manuals or books, of which reference is had especially to:
1. Mc Leod and Welford, "The Classical Guitar Design and Construction", The Dryad Press, Woodridge, New Jersey, page 16 describing a block file; and page 90 describing the shaping of a fret.
2. Sloane, "Guitar Repair", E. P. Dutton and Co., Inc., New York (1973), pages 41-42 describe a technique for rounding the frets.
3. Staff of Guitar Player Magazine, "Guitar Repair Manual", Oak Publications, New York, page 13 describes fret leveling and shaping.
4. Teeter, "The Acoustic Guitar, Adjustment, Care, Maintenance and Repair", University of Oklahoma Press, (1975) pages 109, 110 and 106, describe refinishing of frets.
These describe essentially the methods used either by do-it-yourself fret refinishers or by professional fret refinishers. It should be noted that the strings have been removed and no mention of "relief" is made. Often, even professional fret refinishers do not take into account the fingerboard relief resulting from the proper tuning and design of the guitar. Some profession techniques are guarded secrets and not generally known.
The relief, as is known in the art, is the slight bowing or bending of the fingerboard which helps avoid buzzing caused by the low clearance between the strings and frets over which the string must pass. The removal of the strings from the instrument tension on the fingerboard and the amount of relief therefore becomes less. Thus the top surfaces of the frets are slightly differently aligned with respect to each other when the strings have been released as compared to when the instrument is properly tuned and under tension as a result of the taut strings.
Additionally, usual prior art methods of refinishing frets do not result in a properly shaped fret. To illustrate this, reference is had to FIG. 1A which shows a side view of a fingerboard 11 with a properly shaped fret 12 embedded therein. A string 13 of the stringed instrument will be tangent to the center portion of the fret, when pressed against the fret as shown. FIG. 1B, similar to FIG. 1A, shows a fret 12a leveled below any groove or wear mark formed in the fret 12 by the string 13, using the prior art method. It can be seen especially that the string 13, when pressed against the fret 12a does not leave the surface of the fret 12a until near the edge. This results in a slightly shorter effective string length and therefore a slightly sharper note.
FIG. 1C shows a fret peaked or polished according to the usual prior art method described above. It can be seen that the fret 12b still does not have the shape of a fret 12 which the manufacturer intended. The string is not tangent to the center of the fret 12b but rather extends across a slight area on the top of the fret 12b thus resulting in a slightly sharper note similar to but not as pronounced an effect which would be obtained with a fret 12a as shown in FIG. 1B.
Additionally the effect of relaxing the relief of the fingerboard by removal of the strings would be such as to make the frets non-symmetrical or misaligned with respect to each other and the instrument when the relief is once more attained by replacing the strings. The result of this condition of non-symmetry and misalignment during the leveling procedure may be incorrect clearances causing interferences of the vibrating string and those frets immediately adjacent to the fret being played. This interference is objectionable in as much as it creates a buzzing or rattling sound.
It is to be noted that many professional fret refinishers will allow for the relief of the fingerboard when refinishing the frets, but a properly shaped fret is not always obtained and the fees charged by professional refinishers are often considerable. Instructions for the refinishing of frets by non-professional fret refinishers, that is the usual stringed instrument player, do not take into account the relief of the fingerboard and usually result in a fret with the shape 12b shown in FIG. 1C.